My Vista64 machine is taking long time to get the 'usable' on startup; I believe that it appears to take about a half hour. I also seek the whole thing many programs that ran on startup were removed, processes examined, virus checks. Then I uninstalled a group of old programs I barely ever used them, then I uninstalled more, all this did was made the difficulty more badly.
Then I looked at my "quick launch" toolbar, the average one integrated in the Windows taskbar, if you desire to enable it, I have a LOT of shortcuts there - I saw numerous of common icons, generally I expect since Windows had searched for the targets or the target's icon at least, but couldn't find them? They were gone as I had just uninstalled their target programs and an uninstall does not remove a shortcut you physically create. So one by one I deleted all generic icon shortcuts from the desktop. When I right clicked on each one there was a LONG pause, most probably while more searching was going on? I have 6 hard drives and huge space; if it was searching the search would take a long time.
Some months ago I had physically moved two of the programs that were in the quick launch bar. I think this was what source the early problem. Besides, once all the shortcuts with the general icons were deleted my startup times have returned to normal! Huge difference. I'm also browsing on the net freely in less than a minute as evaluate to about 4 minutes before.

I had become influenced that the problem was 'winrot' - the slow filth of a Windows install which allegedly happens for some indistinct and hard to pin down registry errors or bloat that can be difficult or impossible to locate. In this example that wasn't it and my faith in my long status Vista install has been also restored. It's running like new system in it.